LXR linux/arch/unicore32/kernel/hibernate.c

   1/*
   2 *  linux/arch/unicore32/kernel/hibernate.c
   3 *
   4 * Code specific to PKUnity SoC and UniCore ISA
   5 *
   6 *      Maintained by GUAN Xue-tao <gxt@mprc.pku.edu.cn>
   7 *      Copyright (C) 2001-2010 Guan Xuetao
   8 *
   9 * This program is free software; you can redistribute it and/or modify
  10 * it under the terms of the GNU General Public License version 2 as
  11 * published by the Free Software Foundation.
  12 */
  13
  14#include <linux/gfp.h>
  15#include <linux/suspend.h>
  16#include <linux/bootmem.h>
  17
  18#include <asm/page.h>
  19#include <asm/pgtable.h>
  20#include <asm/pgalloc.h>
  21#include <asm/suspend.h>
  22
  23#include "mach/pm.h"
  24
  25/* Pointer to the temporary resume page tables */
  26pgd_t *resume_pg_dir;
  27
  28struct swsusp_arch_regs swsusp_arch_regs_cpu0;
  29
  30/*
  31 * Create a middle page table on a resume-safe page and put a pointer to it in
  32 * the given global directory entry.  This only returns the gd entry
  33 * in non-PAE compilation mode, since the middle layer is folded.
  34 */
  35static pmd_t *resume_one_md_table_init(pgd_t *pgd)
  36{
  37        pud_t *pud;
  38        pmd_t *pmd_table;
  39
  40        pud = pud_offset(pgd, 0);
  41        pmd_table = pmd_offset(pud, 0);
  42
  43        return pmd_table;
  44}
  45
  46/*
  47 * Create a page table on a resume-safe page and place a pointer to it in
  48 * a middle page directory entry.
  49 */
  50static pte_t *resume_one_page_table_init(pmd_t *pmd)
  51{
  52        if (pmd_none(*pmd)) {
  53                pte_t *page_table = (pte_t *)get_safe_page(GFP_ATOMIC);
  54                if (!page_table)
  55                        return NULL;
  56
  57                set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_KERNEL_TABLE));
  58
  59                BUG_ON(page_table != pte_offset_kernel(pmd, 0));
  60
  61                return page_table;
  62        }
  63
  64        return pte_offset_kernel(pmd, 0);
  65}
  66
  67/*
  68 * This maps the physical memory to kernel virtual address space, a total
  69 * of max_low_pfn pages, by creating page tables starting from address
  70 * PAGE_OFFSET.  The page tables are allocated out of resume-safe pages.
  71 */
  72static int resume_physical_mapping_init(pgd_t *pgd_base)
  73{
  74        unsigned long pfn;
  75        pgd_t *pgd;
  76        pmd_t *pmd;
  77        pte_t *pte;
  78        int pgd_idx, pmd_idx;
  79
  80        pgd_idx = pgd_index(PAGE_OFFSET);
  81        pgd = pgd_base + pgd_idx;
  82        pfn = 0;
  83
  84        for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
  85                pmd = resume_one_md_table_init(pgd);
  86                if (!pmd)
  87                        return -ENOMEM;
  88
  89                if (pfn >= max_low_pfn)
  90                        continue;
  91
  92                for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD; pmd++, pmd_idx++) {
  93                        pte_t *max_pte;
  94
  95                        if (pfn >= max_low_pfn)
  96                                break;
  97
  98                        /* Map with normal page tables.
  99                         * NOTE: We can mark everything as executable here
 100                         */
 101                        pte = resume_one_page_table_init(pmd);
 102                        if (!pte)
 103                                return -ENOMEM;
 104
 105                        max_pte = pte + PTRS_PER_PTE;
 106                        for (; pte < max_pte; pte++, pfn++) {
 107                                if (pfn >= max_low_pfn)
 108                                        break;
 109
 110                                set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
 111                        }
 112                }
 113        }
 114
 115        return 0;
 116}
 117
 118static inline void resume_init_first_level_page_table(pgd_t *pg_dir)
 119{
 120}
 121
 122int swsusp_arch_resume(void)
 123{
 124        int error;
 125
 126        resume_pg_dir = (pgd_t *)get_safe_page(GFP_ATOMIC);
 127        if (!resume_pg_dir)
 128                return -ENOMEM;
 129
 130        resume_init_first_level_page_table(resume_pg_dir);
 131        error = resume_physical_mapping_init(resume_pg_dir);
 132        if (error)
 133                return error;
 134
 135        /* We have got enough memory and from now on we cannot recover */
 136        restore_image(resume_pg_dir, restore_pblist);
 137        return 0;
 138}
 139
 140/*
 141 *      pfn_is_nosave - check if given pfn is in the 'nosave' section
 142 */
 143
 144int pfn_is_nosave(unsigned long pfn)
 145{
 146        unsigned long begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
 147        unsigned long end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
 148
 149        return (pfn >= begin_pfn) && (pfn < end_pfn);
 150}
 151
 152void save_processor_state(void)
 153{
 154}
 155
 156void restore_processor_state(void)
 157{
 158        local_flush_tlb_all();
 159}
 160